Hey all,
In my (humble fishraider forum virgin) opinion the problem with eating big fish can be summed up in one word...
'BIOMAGNIFICATION'
A simple explanation of what this means is...
Each time a species which is contaminated with say heavy metals or dioxins etc is eaten by a species higher up the food chain you basically multiply the concentration (measured in Parts Per Million or PPM) of contaminants ten fold (x10) ! ! !
This is because big fish eat lots of little fish and all the small amounts of toxins in the little fish add up in the big fishes body. Same thing happens to us as we're too part of the food chain, so if you eat lots of big fish this may POTENTIALLY make you much sicker much quicker!
Having said that let me say this ... Obviously pelagic species such as kings are feeding heaps in open waters on non contaminated fish and only part of their diet is in closed waters. Which I guess may explain their relatively low toxicity levels.
I suppose species such as mulloway are feeding far more within closed waters and much further upstream where concentrations of pollutants are generally higher resulting in higher concentrations of toxins in these fish.
Small fish such as bream may feed entirely within closed waters much further upstream resulting in very high concentrations of toxins.
So my guess is the recommended dietary intake advice is sound and based on extensive research except I can't see anyone actually weighing fish before eating and keeping a consumption diary so for me the key is m-o-d-e-r-a-t-i-o-n and I guess if in doubt pelagics are generally a safer bet.
PS. I am such a nerd, I was sure my first post was going to be a report about catching a bunch of huge kings or yellowfin or something... oh well stay tuned I'll do my best to make that my second post ! ! !
Cheers
Streaker 4.58